There are four basic techniques that have been employed in the manufacture
of stone tools. These four techniques are:

Hammer and Anvil

Bipolar

Hard Hammer

Soft Hammer

The following sections will explain each of these techniques in turn.

Hammer and Anvil Technique

The hammer and anvil technique for removing flakes from a core is perhaps
one of the oldest documented methods. It is quite effective for making large
flakes for direct use as tools, or for use as blanks from which shaped tools can
be made. This technique entails using the core as a hammer, and striking the
edge of the core against a large, stationary rock (the anvil) in order to remove
a flake.

There are a number of disadvantages to the technique, however. The
principal disadvantage is that the flintknapper does not have a great deal of
control over the flake removal process. A second disadvantage is that the
flakes removed in this manner fly up and away from the anvil, becoming very
dangerous projectiles for anyone standing nearby.

The bipolar technique is a modification of the hammer and anvil technique.
In bipolar flaking, the core is placed on the anvil for support, and then struck
with a large heavy hammer. The compression from both ends of the core cause it
to shatter into hundreds of flakes, some of which will be large enough, and of
the right shape for use as tools. This technique is often found in areas where
the only reliable source of workable stone is rounded river cobbles that are
extremely hard to work in any other fashion.

The principal disadvantages to the bipolar technique are that there is very
little control over the flake making process, and it wastes a great deal of raw
material to get a few usable flakes.

Both of the techniques already discussed depend on percussion to remove a
flake from a core. Hard hammer percussion, as the name implies, relies on the
same principles, but provides more control over how the flake is detached. In
hard hammer flaking, the core is held in one hand, and struck with a
hammerstone. Technically, the hammerstone must be made of a material that is
harder that the core material so that it does not shatter in the flintknapper's
hands. By using hard hammer percussion, the experienced flintknapper has very
good control over where the flake will be detached and the size of the flake.

While both hard and soft hammer methods take advantage of the fact that
cyrptocrystalline rocks all break according to the Hertzian Cone principle,
soft hammer percussion adds an added dimension of control to the process. In
soft hammer flaking, a hammer or baton of material softer that the core is used.
This could be soft limestone, deer antler, bone, or hardwood. Striking the
core with the baton initiates a fracture according to the cone principle, but
the soft hammer material tends to catch the edge of the flake, allowing the
experienced flintknapper to actually help pull the flake off of the core. This
works because the stone is actually shearing or tearing, rather than shattering,
so it is a controlled breakage process.

Pressure flaking is used for the final trimming and sharpening of the edges
of stone tools. It is also often the method employed to sharpen tools during
their use-life. Generally, pressure flaking is done with a durable, flexible
tool such as a piece of antler tine. The technique takes advantage of the
elasticity of the stone to actually peel thin flakes off of the core material.
The more elastic the material, the better it is for pressure flaking. Thus, the
finest examples of long, thin pressure flakes come from obsidian specimens.